Vibration responsive switch



July 25, 1967 K. 1.. OHLSON 3,333,073

VIBRATION RESPONSIVE SWITCH Filed Nov. 16, 1965 F/GX/ l q I M ATTORNEY United States Patent 3,333,073 VIBRATION RESPGNSIVE SWITCH Kurt Lennart Ohlson, Farsta, Sweden, assignor to Aktiebolaget Electrolux, Stockholm, Sweden, a corporation of Sweden Filed Nov. 16, 1965, Ser. No. 508,046 Claims priority, application Sweden, Nov. 17, 1964, 13,877/64 8 Claims. (Cl. ZOO-61.45)

My invention relates to a vibration responsive switch.

The object of my invention is to provide an improved switch of this type having a movable operating contact arm biased toward a first position and held at a second position by a force applying member which becomes ineffective under vibratory force and enables the contact arm to move toward its first biased position, and to provide a fabricated construction which is reliable in operation and requires relatively few parts and is simple and inexpensive to manufacture.

Further objects and advantages of the invention will become apparent as the description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In the drawing, FIG. 1 is an elevational view, partly broken away and in section, of a washing machine provided with a vibratory switch embodying my invention; FIG. 2 is an enlarged exploded perspective view, partly broken away and in section, of the vibratory switch embodied in the washing machine shown in FIG. 1 and a diagrammatic representation of an electric circuit for the washing machine motor in which the switch is connected; FIG. 3 is a vertical sectional view of the switch shown in FIG. 2 with the operating contact arm thereof in one position; and FIG. 4 is an elevational view, partly broken away and in section, of the vibratory switch shown in FIG. 3 with the operating contact arm thereof in another position.

In FIG. 1 I have shown my invention in connection with a washing machine comprising an outer shell or housing 11 having a base 12 provided with supporting legs 14. The outer shell 11 further includes upstanding side walls 15 and a top 16 which, together with the base 12, defines a space 17 within the outer shell 11. In the space 17 is positioned an open-top container or receptacle 18, the upper end of which is flexibly connected at 19 in any suitable manner to the side walls 15 at the vicinity of the top 16. By way of example, a corrugated collar formed of elastomeric material, for example, may be employed to provide the flexible connection 19.

An apertured cylinder or drum 20 is mounted for rotation about a horizontal axis within the receptacle 18. Clothes to be washed are introduced into the cylinder 20 which may have an opening in the peripheral surface thereof adapted to be closed by a sliding door (not shown) and to which access may be had by a cover 21 hinged (not shown) to the top 16. The cylinder 20 is provided with stub shafts 22 which project axially from its ends and are journaled at the upper ends of upstanding brackets 23 which are disposed in the space 17. The brackets 23 at their lower ends are fixed to a horizontally disposed frame 24 resiliently supported at 25 to the base 12.

The receptacle 18 serves as a washing zone for clothes held in the cylinder or drum 20. Liquid may be introduced into the receptacle 18 and withdrawn therefrom in any suitable manner (not shown) to perform a sequence of operations including washing and rinsing periods and periods for extracting liquid from clothes by centrifugal force or centrifuge action.

The stub shafts 22 at the regions they pass through openings in the washing receptacle 18 are provided with liquid-tight seals (not shown).

The apertured cylinder 20 is driven by an electricrnotor 26 which is mounted on the resiliently supported frame 24 and provided with a shaft 27. An endless belt 28, which is disposed about pulleys 29 and 30 fixed to the motor shaft 27 and one of the stub shafts 22, respectively, form a part of the mechanism to render the motor 26 operable to drive the apertured cylinder 20 within the washing receptacle 18. As shown in FIG. 1, the apertured cylinder desirably is provided with spaced axially extending ridges 31 which extend radially inward toward the axis of the cylinder 20 and tend to carry clothes upward within the cylinder when it rotates about its axis. When the clothes reach a higher level within the cylinder 20 at which the ridges become ineffective to hold the upward moving clothes, the clothes fall toward the bottom of the cylinder.

As diagrammatically illustrated in FIG. 2, electrical energy may be supplied to the motor 26 from a suitable source of supply 32 through conductors 33 and 34. The conductors 33 and'34 are connected to the motor 26, a switch 35 being connected in the conductor 34 to provide a circuit for the motor 26 which may also include other controls to regulate the speed at which the motor is driven during the washing, ing periods.

When the clothes being washed are not evenly distributed at the inner surface of the cylinder 20, objectional vibration of the washing machine 10 may occur. This is especially true when the cylinder 20 is being driven by the motor 26 at a sufiiciently high speed to extract liquid from clothes by centrifugal force.

In accordance with my invention, I provide the switch 35 which is closed and completes the circuit for the motor 26 during normal operation of the washing machine 10 and is actuated to open the motor circuit responsive to objectional vibration of the washing machine. The switch 35 comprises contact arms which include leaf springs 36' and 37' having cooperating contacts 36" and 37", respectively. The leaf spring 36 and contact 36" mounted thereon function as an operating contact arm 36 which is resiliently biased toward its first upright or erect position shown in FIG. 3.

When force is applied to the operating contact arm 36 to effect movement thereof toward the right in FIG. 3, in a manner which will be explained presently, it is moved from its first position against its bias to its second position illustrated in FIG. 4. The leaf spring 37' and contact 37" mounted thereon function as a contact arm 37 which cooperates with the contact arm 36, the contact 36 engaging the contact 37" in FIG. 4 to complete the illustrated circuit for the motor 26. While the contact arm 37 in the preferred embodiment illustrated and being described is resilient and includes the leaf spring 37', it should be understood that the contact arm 37 may be nonresilient, if desired.

Blocks 38 and 39 formed of insulating material are fixed by screws 40 to the upstanding side wall 41 of a housing or shell 41, the screws 40 also functioning to anchor the lower ends of the leaf springs 36' and 37 to the blocks 38 and 39, respectively. The housing 41 defines a space 42 which is closed by a removable top or cover 43 resiliently held on the housing 41 at the open end thereof, as shown in FIGS. 3 and 4. l

The housing 41 is cylindrical and provided with openings 44 and 45 at diametrically opposing sides of its side wall 41' approximately at the level of the contacts 36" and 37". An elongated bar or rod 46, which is of cylindrical shape and axially movable in the openings 44 and 45, includes an enlarged head 47 which is of larger diameter than the opening 44 and positioned outside the housing 41. When the enlarged head 47 bears against the rinsing and liquid extractouter surface of the housing 41, the outer face of the head 47 engages the opening contact arm 36 when the latter is substantially straight, as illustrated in FIG. 3, and biased to its first upright or erect position.

When the elongated bar 46 is moved to the right in FIG. 3, the enlarged head 47 thereof imparts movement to the operating contact arm 36 against the bias thereof and the contact arm 36 flexes toward the right. When the head 47 is moved a sufficient distance from the housing 41, the contact 36" mounted thereon engages the contacts 37" and flexes the contact arm 37 toward the right, as shown in FIG. 4, to complete the illustrated circuit for the motor 26.

The elongated bar 46 also includes an intermediate portion 48 and an end portion 49 which are axially movable in the housing openings 44 and 45, respectively. The intermediate portion 48 is of smaller diameter than that of the head 47, and the end portion 49 in turn is of smaller diameter than that of the intermediate portion 48. With this construction, the bar 46 is formed with a shoulder 50 between the head 47 and intermediate portion 48, and a shoulder 51 between the intermediate portion 48 and end portion 49. The shoulder 50 bears against the outer surface of the housing 41 about the opening 44 therein and is urged to such position by the operating contact arm 36 when the latter is erect and biased to its first position. The shoulder 51 is located in the central region of the space 42 and left of the vertical axis of the housing 41 when the shoulder 50 bears against the outer surface of the side wall 41' of the housing, as shown in FIG. 3. It will now be understood that the elongated bar 46 functions as a force applying member which is movable toward and from the operating contact arm 36 in a first path of movement. The shoulder 51 constitutes a wall of the member 46 which is transverse or normal to the first path of movement of the member 46. As shown in FIG. 4, a lug or pin 52 extending vertically upward from the top of a cylindrical shaped member 53 is located in the path of movement of the shoulder or wall 51 and functions to hold the rod or first member 46 only when the latter is in its force applying position. In FIG. 4 the operating contact arm 36 is biased toward its erect or first position and urges the member 46 toward the left so that the wall or shoulder 51 is firmly held against the pin 52 under normal operating conditions of the washing machine 10.

As best seen in FIG. 3, the member 53, which desirably is relatively heavy, is vertically disposed and nests in a pocket 54 formed in the space 42 by a plurality of vertical ribs 55 which extend radially inward from the inner surface of the side wall 41 of the housing 41 and are distributed within the space 42. The vertical ribs 55, which are fixed to the inner surface of the housing 41 in any suitable manner and spaced from one another, are provided with flanges 56 at their lower ends which extend radially inward at the lower open end 4 of the housing.

.The member 53 is resiliently supported on the flanges 56 by a conical-shaped spring 57, the large bottom end of the spring bearing against the top surfaces of the flanges 56 and the small top end thereof bearing against the bottom of the member 53. Hence, the entire dead weight of the member 53 is resiliently supported by the spring 57. The conical-shaped spring 57 serves as a compression spring to bias the member 53 vertically upward and in turn urge the pin 52 upward against the end portion 49 of the elongated member 46 at the wall or shoulder 51. This action of the spring 57 is opposed by the downward movement imparted to the member 53 by the force of gravity. In order that the member 53 can bodily move freely up and down in the pocket 54, gaps 58 of suflicient size are provided between the outer peripheral surface of the vertically movable member 53 and the inner ends of the ribs 55. With this construction the member 53 nests in the pocket 54 with sufficient horizontal play throughout the height of the ribs 55 which project upward a slight distance from the top of the member 53, as shown in FIG. 3.

The side wall 41' of the housing 41 diametrically opposite the contact arms 36 and 37 is provided with bosses 59 which are in vertical alignment and adapted to receive screws 60 for rigidly mounting the housing 41 on an upright angle member 61 at the junction of two abutting side walls 15 of the outer shell 11.

The housing 41 is also formed with a hollow boss 62 which defines the opening 45. The outer end of the boss 62 is flush with the outer surface of the outer shell 11 and the end portion 49 of the bar or member 46 projects outside the outer shell, the housing 41 and contact arms 36 and 37 of the switch 35 being positioned in the space 17 within the outer shell.

Washing machines like the washing machine 10 usually are provided with suitable controls (not shown) to Wash, rinse and extract liquid from clothes at appropriate periods in a washing cycle. Before such a washing cycle is started the outer projecting part 49a of the end portion 49 of the bar 46, which may be referred to as a reset key, is pushed inward at the boss 62 to move the bar or first member 46 from the position shown in FIG. 3 to the position shown in FIG. 4. In FIG. 3 the pin or lug 52 is in vertical alignment with a part of the intermediate portion 48 of the elongated bar or first member 46 and bears against the outer surface thereof. Therefore, in FIG. 3 the pin or lug 52 is not in the path of movement of the shoulder or wall 51 and the enlarged head 47 bears against the outer surface of the side wall 41' of the housing 41 and ineffective to close the contacts 36 and 37" of the switch 35.

When the reset key 49a is pushed inward, the bar or first member 46 moves toward the right in FIG. 3 responsive to force applied thereto, thereby moving the wall or shoulder 51 horizontally past the vertical pin 52. When this occurs the pin 52, which is urged upward by the compression spring 57, moves against the end portion 49 of the first member 46. In this particular position of the pin 52, which is shown in FIG. 4, the pin bears against the shoulder or wall 51 and is in the path of movement thereof and holds the bar 46 in its FIG. 4 position. Under these conditions, as previously explained, the contact 36" engages the contact 37" and completes the motor circuit illustrated and renders the motor 26 operable when the washing cycle is initiated by suitable controls, as explained above.

The switch 35 remains closed under normal operating conditions of the washing machine 10. The washing machine 10 occasionally is subject to abnormal vibration which may occur when the washing load in the cylinder 20 becomes unbalanced while liquid is being extracted by centrifuge action. Under such operating conditions the abnormal vibration of the washing machine 10 imparts downward bodily movement to the member 53, such downward movement of the member 53 being effected with the aid of the force of gravity against the upward bias of the spring 57. For this reason, the member 53 is sufficiently heavy so that, when the washing machine 10 is subject to abnormal vibration, the force of gravity will promote the downward bodily movement imparted to the member 53 and cause the latter to move vertically downward a sufficient distance below the wall or shoulder 51 to enable the elongated bar or first member 46 to move from its force applying position shown in FIG. 4 to its ineffective position shown in FIG. 3 by the bias of the leaf spring 36'. When this occurs, the contacts '36" and 37" are separated to open the circuit for the motor 26 and stop the operation of the washing machine 10-.

When the washing machine 10 stops operating, the washing load in the cylinder 20 may be manually redistributed, so that the washing load will no longer be unbalanced to such an extent that the washing machine 10 will be subject to abnormal vibration. Thereafter, the operation of the washing machine can be resumed by pushing the reset key 49a so that contact 36' engages contact 37 and the pin 52 will bear against the wall or shoulder 51 of the member 46 to prevent the contacts 36" and 37" from being separated.

Although I have illustrated and described a particular embodiment of my invention, I do not desire to be limited to the particular arrangement set forth, and I intend in the following claims to cover all modifications which do not depart from the spirit and scope of my invention.

I claim:

1. A switch including a movable operating contact arm biased toward a first position and held at a second position by means including a first member movable toward and from the contact arm in a first path of movement, the contact arm having a contact thereon, the first member being movable from a first position to a second force applying position responsive to force applied thereto to force the contact arm to its second position, the first member having a wall transverse to the first path of movement, a second member movable toward and from the first member in a second path of movement transverse to the first path of movement, the second member including a part which is movable into the path of movement of the wall and operable to hold the first member in its second force applying position, means for resiliently supporting the entire dead weight of the second member, the resilient supporting means functioning to move the part into the path of movement of the wall only when the first member is in its second force applying position and the contact arm is in its second position, the second member being movable from the first member in its second path of movement to release the part from the wall of the first member whereby the contact arm will move toward its biased first position and the first member will move from its second force applying position to its first position, and a mount for the second member, the mount including means providing a vertically extending guideway in which the second member is bodily movable freely to promote movement of the part thereof from the wall of the first member under vibratory force with the aid of the force of gravity.

2. A switch as set forth in claim 1 in which the mount comprises a housing defining a space, the guideway means being disposed within the housing and forming a pocket open .at the top and in which the second member rests and is bodily movable, and the resilient means supporting the second member comprising spring means in the pocket at the bottom of the second member.

3. A switch as set forth in claim 1 in which the mount comprises a housing which has an upstanding side wall and defines a space, the guideway means being disposed in the space to receive the second member for vertical movement therein, the first member being disposed above the top of the second member and comprising an elongated element, diametrically opposing sides of the side wall having openings to receive the elongated element, the element being horizontally disposed and axially movable in the openings, and the element having a portion rojecting outside the housing serving as a reset key.

4. A switch as set forth in claim 1 in which the mount comprises a housing having an upstanding side wall, the guideway means comprising a plurality of spaced vertical ribs distributed about the inner surface of the side Wall of the housing and extending radially inward therefrom, the lower ends of the vertical ribs having flanges which extend radially inward from the side wall of the housing, the ribs and flanges defining a pocket having an open top and in which the second member nests and is bodily movable, the gaps between the inner ends of the vertical ribs and the peripheral surface of the second member being sufiicient to provide adequate horizontal play at all levels 6 of the second member to enable the latter to move freely in a vertical direction in the pocket, and the resilient supporting means comprising coil spring means having its opposing ends respectively engaging the top surfaces of the flanges and the bottom of the second member.

5. A switch comprising a first member movable back and forth in a first path of movement, an operating contact, the operating contact being arranged to be moved back and forth responsive to back and forth movement of the first member, means biasing at least the first member in one direction to a first position, whereby movement of the operating contact toward a first position is effected, the first member beingmovable against said bias from its first position to a second position responsive to force applied thereto, the operating contact also being movable from a first position to a second position responsive to movement of the first member to its second position, the first member having -a wall transverse to the first path of movement, a second member movable toward and from the first member in a second path of movement transverse to the first path of movement, the second member including a part which is movable into the path of movement of the wall and operable to hold the first member in its second position, means for resiliently supporting the entire dead weight of the second member, the resilient supporting means functioning to move the part into the path of movement of the wall only when the first member is in its second position and the operating contact is in its second position, the second member being movable from the first member in its second path of movement to release the part from the Wall of the first member whereby the first member will move toward its first position responsive to said bias and the operating contact also will move from its second position toward its first position, and a mount for the second memher, the mount including means providing a vertically extending guideway in which the second member is bodily movable freely to promote movement of the part thereof from the wall of the first member under vibratory force with the aid of the force of gravity.

6. A switch as set forth in claim 5 which includes a leaf spring, and said biasing means comprising the leaf spring, the leaf spring functioning as an operating contact arm and having the operating contact thereon.

7. A switch as set forth in claim 5 in which the mount comprises a housing defining a space, the guideway means being disposed within the housing and forming a pocket open at the top and in which the second member nests and is bodily movable, and the resilient means supporting the second member comprising a spring in the pocket at the bottom of the second member.

8. A switch as set forth in claim 5 in which the mount comprises a housing which has an upstanding side wall and defines a space, the guideway means being disposed in the space to receive the second member for bodily vertical movement therein, the first member being disposed above the top of the second member and comprising an elongated element, diametrically opposing sides of the side wall having openings to receive the elongated element, the element being horizontally disposed and axially movable in the openings, and the element having a portion projecting outside the housing serving as a reset key.

References Cited UNITED STATES PATENTS 2,297,095 9/1942 Bassett 200-6l.48 2,445,873 7/ 1948 Chambers 20061.48 3,089,929 5/1963 Murphy 20061.S

BERNARD A. GILHEANY, Primary Examiner.

V I. I. BAKER, H. B. GILSON, Assistant Examiners. 

1. A SWITCH INCLUDING A MOVABLE OPERATING CONTACT ARM BIASED TOWARD A FIRST POSITION AND HELD AT A SECOND POSITION BY MEANS INCLUDING A FIRST MEMBER MOVABLE TOWARD AND FROM THE CONTACT ARM IN A FIRST PATH OF MOVEMENT, THE CONTACT ARM HAVING A CONTACT THEREON, THE FIRST MEMBER BEING MOVABLE FROM A FIRST POSITION TO A SECOND FORCE APPLYING POSITION RESPONSIVE TO FORCE APPLIED THERETO TO FORCE THE CONTACT ARM TO ITS SECONDPOSITION, THE FIRST MEMBER HAVING A WALL TRANSVERSE TO THE FIRST PATH OF MOVEMENT, A SECOND MEMBER MOVABLE TOWARD AND FROM THE FIRST MEMBER IN A SECOND PATH OF MOVEMENT TRANSVERSE TO THE FIRST PATH OF MOVEMENT, THE SECOND MEMBER INCLUDING A PART WHICH IS MOVABLE INTO THE PATH OF MOVEMENT OF THE WALL AND OPERABLE TO HOLD THE FIRST MEMBER IN ITS SECOND FORCE APPLYING POSITION, MEANS FOR RESILIENTLY SUPPORTING THE ENTIRE DEAD WEIGHT OF THE SECOND MEMBER, THE RESILIENT SUPPORTING MEANS FUNCTIONING TO MOVE THE PART INTO THE PATH OF MOVEMENT OF THE WALL ONLY WHEN THE FIRST MEMBER IS IN ITS SECOND FORCE APPLYING POSITION AND THE CONTACT ARM IS IN ITS SECOND POSITION, THE SECOND MEMBER BEING MOVABLE FROM THE FIRST MEMBER IN ITS SECOND PATH OF MOVEMENT TO RELEASE THE PART FROM THE WALL OF THE FIRST MEMBER WHEREBY THE CONTACT ARM WILL MOVE TOWARD ITS BIASED FIRST POSITION AND THE FIRST MEMBER WALL MOVE FROM ITS SECOND FORCE APPLYING POSITION TO ITS FIRST POSITION, AND A MOUNT FOR THE SECOND MEMBER, THE MOUNT INCLUDING MEANS PROVIDING A VERTICALLY EXTENDING GUIDEWAY IN WHICH THE SECOND MEMBER IS BODILY MOVABLE FREELY TO PROMOTE MOVEMENT OF THE PART THEREOF FROM THE WALL OF THE FIRST MEMBER UNDER VIBRATORY FORCE WITH THE AID OF THE FORCE OF GRAVITY. 